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Biomedical subjects

I J Huang

Publications and source records attributed to I J Huang.

7 recordsLinked to original sources
PubMed2001

Assays for angiotensin converting enzyme inhibitory activity.

A colorimetric method and a capillary electrophoresis procedure were developed for quantifying histidyl-leucine and hippurate, respectively. The colorimetric method is sensitive (extinction coefficient = 7.5 mM(-1) cm(-1)) and reproducible (CV = 1.7%, n = 5), which is based on a selective chromogenic reaction for histidyl-leucine (lambda(max) = 390 nm) using o-phthalaldehyde. For samples containing unusually high levels of histidine and/or histidyl peptides, the separation-based approach is preferable. The capillary electrophoresis method makes use of an in-capillary microextraction technique; complicated samples can be measured in less than 4 min without pretreatment. Protocols using both methods to measure angiotensin converting enzyme inhibitory activity were proposed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

Time course of cerebral infarction in the middle cerebral arterial territory: deep watershed versus territorial subtypes on diffusion-weighted MR images.

PURPOSE: To examine possible differences between the evolution of cerebral watershed infarction (WI) and that of territorial thromboembolic infarction (TI) by using diffusion-weighted (DW) and T2-weighted magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps. MATERIALS AND METHODS: Fourteen patients with TI and nine with WI underwent MR imaging from the acute to chronic infarction stages. ADC maps were derived from DW images. Lesion-to-normal tissue signal intensity ratios on ADC maps (rADC), echo-planar T2-weighted images, and DW images were calculated. Lesion volumes at acute or early subacute infarction stages were measured on DW images, and final lesion volumes were estimated on fluid-attenuated inversion-recovery images. RESULTS: Analysis of variance revealed a significant difference in temporal evolution patterns of rADC between WI and TI (P <.001). rADC pseudonormalization following TI began about 10 days after symptom onset, but that following WI did not occur until about 1 month after symptom onset. The Pearson correlation coefficient between final and initial infarct volumes was 0.9899 for both infarction subtypes, indicating that the initial ischemic injury volume measured at the acute or early subacute stage predicted the final lesion volume fairly well. CONCLUSION: The evolution time of ADC is faster for TI than for WI. This difference, which likely originates from the different pathophysiologic and hemodynamic features of the two infarction types, might account for the relatively large range of ADC values reported for the time course of ischemic strokes.

Acute Disease↗
PubMed1999

Decrease in nucleophosmin/B23 mRNA and telomerase activity during indomethacin-induced apoptosis of gastric KATO-III cancer cells.

The mRNA expression of nucleophosmin/B23 in gastric cancers (T) and the matched adjacent "normal" gastric mucosa (N) obtained from patients without any preoperative treatment were determined. Telomerase activity was detected in tumor tissues from six of seven patients. Analysis of the adjacent "normal" gastric mucosa in the same patients revealed all seven were negative for telomerase activity. In comparing clinical data for all seven patients, the stages of cancer seemed to be associated with T/N nucleophosmin/B23 mRNA expression. Cancers of later stages seemed to have higher T/N nucleophosmin/B23 mRNA ratio. After 3-4 days of 1 mM indomethacin treatment about 60-85% of gastric cultured KATO III cancer cells exhibited the features with highly condensed nuclei and decrease in cell size. Concomitant with the increase in the percentage of KATO III cells exhibiting the morphological features of apoptosis, there was a decrease in the viability of cells as determined by exclusion of trypan blue. A decline in telomerase activity in indomethacin-treated versus untreated cells was observed over times (2-4 days). The steady-state level of nucleophosmin/B23 mRNA, as determined by the levels of radioactivity of the hybridizing bands also decreased during the indomethacin treatment. At some times after the removal of indomethacin, cell growth and telomerase activity resumed in little extent (approx. 60%). When nucleophosmin/B23 antisense oligonucleotide was included in the cell culture upon removal of indomethacin, virtually no recovery of cell growth and telomerase activity were observed.

Apoptosis↗
PubMed1995

Sequence analyses and antigenic epitope mapping of the putative RNA-directed RNA polymerase of five U.S. bluetongue viruses.

We determined the complete nucleotide sequences of the cognate L1 double-stranded RNA segments of bluetongue virus (BTV) serotypes 2, 11, 13, and 17, which encode the putative RNA-directed RNA polymerase VP1. Each L1 gene contained 3944 nucleotides and was 10 bases shorter than the previously reported L1 gene of BTV 10. A single open reading frame which could encode the reported VP1 protein, 1302 amino acids in size, began with an initiation codon at nucleotides 12-14 and a termination codon at nucleotides 3918-3920. Analyses of the nucleotides of L1 genes and the deduced amino acid sequences of VP1 proteins of the five U.S. BTV serotypes indicated that the most recently isolated BTV-2 serotype from Florida was more distantly related than BTV-10, 11, 13, and 17, which were isolated primarily in the western U.S.A. The results are consistent with our hypothesis that BTVs-10, -11, -13, and -17 are derived from a single and common gene pool, and that BTV-2 belongs to a second, distinct gene pool. These genetic distinctions also reflected well with the known geographic distribution of the five U.S. BTV serotypes in North America. This putative RNA-directed RNA polymerase (149 KDa) was a basic protein, and the deduced amino acid sequences of the VP1 proteins contained seven highly conserved hydrophobic domains and many other sequence motifs which were also found in other known RNA polymerases. Four immunodominant but linear antigenic epitopes conserved among the VP1 of five U.S. BTVs were also been identified and mapped using monospecific oligoclonal antibodies.

Amino Acid Sequence↗
PubMed1993

Conservation of the segment 4 gene sequence and of a leucine zipper motif in VP4 among five US bluetongue viruses.

Full-length cDNA copies of the segment 4 (M1) genes of US Bluetongue viruses serotype-2, -10, -11, -13, and -17 were selectively amplified using genomic double-stranded RNA segments from purified BTV virions as templates and a modified polymerase chain reaction (Clamp-R). They were then cloned into pUC19 plasmids and both strands of several clones were sequenced. The length of all five segment 4 genes is 1981 nucleotides, which is 30 nucleotides shorter than that of the BTV serotype-10 reported by Y. Yu, A. Fukusho, and P. Roy (Nucleic Acids Res. 15, 7206 (1987)). The 5'- and 3'-noncoding regions of all five segment 4 genes are identical among all serotypes. The plus sense strand of the BTV segment 4 gene, which encodes the VP4 protein, possesses a single long open reading frame with an initiation codon (ATG) at nucleotides 9-11 and a stop codon (TAA) at nucleotides 1941-1943. This open reading frame encodes for a protein of 644 amino acid residues with a predicted molecular weight of about 75 kDa and a pI of +7 to +7.9. A potential leucine zipper motif was detected near the carboxyl terminus of the deduced VP4 amino acid sequence. The phylogenetic analysis using the sequences of these five cognate segment 4 genes is consistent with the results of our previous phylogenetic studies of cognate genome segments 5, 6, 8, 9, and 10. Serotype-10, -11, -13, and -17 are closely related and serotype-2 is the most distantly related among the five US BTV serotypes.

Amino Acid Sequence↗
PubMed1992

Evolutionary analyses of five US bluetongue viruses using the cognate S2 genes.

Full-length cDNA copies of S2 genes (segment 8), coding for non-structural protein 2 (NS2) of bluetongue virus serotypes 2, 11, 13 and 17 were selectively synthesized by a modified polymerase chain reaction (Clamp-R) and cloned into the PstI site of the pUC19 plasmid. Each of these S2 cognate genes was 1125 nucleotides in length with an initiation and a termination codon at nucleotides 20-22 and 1082-1084, respectively, resulting in a long open reading frame capable of coding for a protein of 354 amino acids. The deduced amino acid sequence of NS2 protein had a high concentration of lysine and contained a relatively low number of tryptophan and histidine residues. There was a highly conserved hydrophilic region at the carboxyl termini of predicted NS2 proteins in all five BTV serotypes, even though the amino acid sequence in this region in BTV-2 was more variable than in the other four serotypes. There was significant sequence homology of the cognate S2 genes at both the nucleotide and the amino acid levels. Phylogenetic analyses using the S2 gene sequences indicated that BTV-10, -11, -13 and -17 were more closely related and BTV-2 was the most distantly related serotype among the five US bluetongue viruses.

Amino Acid Sequence↗